A maintenance engineer at Grampian Country Pork in Little Wratten, near Haverhill in Suffolk, sustained injuries to his head and face after becoming trapped in machinery.
Following treatment by paramedics and the critical care team from an air ambulance, he was taken to Addenbrookes Hospital in Cambridgeshire.
The man, who is believed to be in his 40s, has not been named. His injuries are thought to be serious but not life-threatening.
A Vion spokesman said the company was grateful to emergency crews and factory staff who had come to the aid of the engineer, and said its “first priority was the welfare of the engineer involved”.
The Health & Safety Executive confirmed that an investigation into the incident was under way.